The present invention relates to an electromagnetic device for halting the motion of a turbocharger waste gate.
To control the speed of the turbocharger and hence the amount of turbo boost imparted to the engine, turbochargers employ a waste gate rotatably positioned within a bypass passage. As engine speed increases so does the velocity of the exhaust stream which will tend to move the waste gate from a closed position toward an open position. Turbocharger boost is controlled by halting further the motion of the waste gate. Prior waste gate control devices have utilized pneumatic controls based upon intake manifold pressure. These pneumatic control devices are typically activated by positive pressure. In smaller engines an additional pump may also be required. These devices have proven ineffective and unreliable due to the vagaries in available pressure.
It is an object of the present invention to provide an electromagnetic waste gate brake. A further object of the present invention is to provide a device that does not display the deficiencies of the prior art.
Accordingly, the invention comprises: a waste gate brake for controlling a waste gate of a turbocharger comprising: a housing defining a chamber and first opening into the chamber; a shaft adapted to be connected to and movable with the motion of a waste gate; first means for defining a magnetic path, for generating an electromagnetic force in such path and for preventing the shaft from moving, thereby preventing the waste gate from moving. In one embodiment the waste gate brake includes a flat plate connected to a hollow shaft and an electromagnet situated below the plate. Upon energizing of the electromagnet it moves toward the plate by the magnetic forces generated. In this condition the axial motion of the shaft and hence the waste gate is restricted since the electromagnet has extrememly limited motion in a direction parallel to the shaft axis. In another embodiment a circular electromagnet is used which interacts with cylindrical split rings to prohibit shaft motion. Additionally the invention is applied to a system for controlling an engine turbocharger.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.